Paper currency validators, often referred to as "bill validators", have enjoyed commercial success in the vending industry for many years. As vending sales move toward higher average values the demand for improved devices increases. Numerous applications, still however, go unfulfilled. For example in the pay telephone industry where sufficient power is virtually unavailable in remote locations the presently available devices consume too much power to be used. Improvement is also needed in validation accuracy especially where high value bills are submitted. Automatic ticket vending, postage stamp vending and the gaming industry require the highest accuracy in validation because high denomination currency must be accepted in these transactions.
In typical bill validators currently available, paper currency is fed into a slot located at the front of the unit, the presence of the bill is detected and it is conveyed into the unit where its validity and denomination is determined. If the bill is acceptable it is then further conveyed into a stacker where it is stored in a compact stack and credit is issued for its value.
In vending equipment it is highly desirable to complete the transaction as quickly as possible and to stack the bills in as compact a stack as possible. The compact stack should be easy to remove and handle at the designated counting location and the stacker should hold as many bills as possible in the space allotted within the vending equipment.
Paper currency can be limp, damp, wrinkled, folded or torn and can create jams in equipment. During bill conveyance and especially stacking is when most jams occur. These can render an entire vending outlet inoperable until service personnel arrive to clear the jam. Thus simple positive acting mechanisms are needed.
Present bill stacker mechanisms are complex and most operate using variations of cam driven pusher plate mechanisms. In these a bill is conveyed by a set of rubber belts along two fixed rails whereupon the bill stops and a pusher plate is activated which forcefully pushes the bill well beyond the fixed rails into the stack then the plate retracts. The operation is perceptibly slow and noisy and does not instill confidence in customers.
U.S. Pat. No. 4,678,072 describes such a system. The system requires a powerful high torque gear head motor, two cams, numerous guide rollers on the fixed rails to reduce friction, four scissor jack arms, numerous pivot pins, gears, pulleys, shafts and several compression springs, a pusher plate and return springs. The use of a pusher plate and fixed rails is typical of conventional stackers available today, however these consume a great deal of premium space which could have been otherwise used to stack additional bills. The many moving parts constitute opportunities for equipment failure and the complexity of these devices makes them costly to repair.
The process of collecting money from existing devices also poses opportunities for improvement. Money collection personnel are required to remove large amounts of money over a period of time from the stackers in vending equipment. Unfortunately the industry is plagued by some dishonest money collectors who steal a few percent of currency from each machine they service. It would be advantageous if light-weight sealed, traceable stackers were available which could be removed entirely from currency validation equipment by the money collector and replaced with empty sealed stackers. If such were the case the seal would have to be broken to steal and the owner of such equipment would know it had been tampered with. However, present stacker devices, are much too heavy, bulky and complex to remove and reinstall in this manner.
The vending industry also requires different capacity stackers, some capable of storing 200, 400 or 1000 bills. Since the known stackers are built permanently onto the validation part of the mechanism this leads to many different models and significant equipment inventory problems for both manufacturers and users alike.
Yet another need of the vending industry is for validator stackers which can vertically stack bills such as is illustrated in U.S. Pat. No. 4,678,072 and also units which can horizontally stack bills, however, this also leads to increased numbers of models.
In other applications stackerless bill validators are desired and bills are allowed to collect in a bin and these are again separate models.